What are your chances of passing DMD on to your child?
DMD is mostly prevalent in males (it only effects the X chromosome and males carry XY chromosomes so it's passed on, there's no way of having it be dormant) and is usually passed down from the mother (females have two X chromosomes, but still have one copy of the correct gene, so if DMD is found in only one of the X's then a woman couldn't have it, but it can still be passed on). The father can also pass on DMD but only to females, because the male passes on his Y chromosome to his son. However, just because a parent might not have DMD does not mean your child cannot have it. During the mid-months of growth in the womb, a mutation could occur in the X chromosome, creating a malfunction in the dystrophin gene, causing Duchenne Muscular Dystrophy, but this possibility is an extremely small chance.
This picture shows how Duchenne is passed on. The son who has the disease is white. The mother and one of her daughters are both carriers and are shown as 1/2 white 1/2 blue. The father and the son and daughter on the right are unaffected and are all blue.
Will You Have Another Child With DMD, How Can You Be Sure?
To know if an unborn child will have DMD, you can use amniocentesis. To find out the chances of passing it on (for women), screening can be done on possible carriers (women only) in the family. The chance of having DMD is not 100% if you are a carrier, but you should refer to a genetic councilor about having kids after the screening is done. There are a few options for testing for DMD. First, a muscle biopsy, which can sometimes determine if the child has muscular dystrophy. The absence or malfunction of the protein dystrophin can be found as well in this test. In addition, DNA testing, this involves looking at the “misprint” in the dystrophin gene. A third option could be electromyogram (EMG) or nerve conduction velocity (NCV) can be performed. In EMG and NCV, electrical pulses are sent into the muscles and nerves, doctors then measure the pulses and nerve activity to see if it is working properly.
What are your chances of passing DMD on to your child?
DMD is mostly prevalent in males (it only effects the X chromosome and males carry XY chromosomes so it's passed on, there's no way of having it be dormant) and is usually passed down from the mother (females have two X chromosomes, but still have one copy of the correct gene, so if DMD is found in only one of the X's then a woman couldn't have it, but it can still be passed on). The father can also pass on DMD but only to females, because the male passes on his Y chromosome to his son. However, just because a parent might not have DMD does not mean your child cannot have it. During the mid-months of growth in the womb, a mutation could occur in the X chromosome, creating a malfunction in the dystrophin gene, causing Duchenne Muscular Dystrophy, but this possibility is an extremely small chance.
For more information on heredity, click here http://www.hemophilia.ca/en/bleeding-disorders/hemophilia-a-and-b/heredity-of-hemophilia/ Note: heredity of hemophilia is the same for DMD
This picture shows how Duchenne is passed on. The son who has the disease is white. The mother and one of her daughters are both carriers and are shown as 1/2 white 1/2 blue. The father and the son and daughter on the right are unaffected and are all blue.
Will You Have Another Child With DMD, How Can You Be Sure?
To know if an unborn child will have DMD, you can use amniocentesis. To find out the chances of passing it on (for women), screening can be done on possible carriers (women only) in the family. The chance of having DMD is not 100% if you are a carrier, but you should refer to a genetic councilor about having kids after the screening is done. There are a few options for testing for DMD. First, a muscle biopsy, which can sometimes determine if the child has muscular dystrophy. The absence or malfunction of the protein dystrophin can be found as well in this test. In addition, DNA testing, this involves looking at the “misprint” in the dystrophin gene. A third option could be electromyogram (EMG) or nerve conduction velocity (NCV) can be performed. In EMG and NCV, electrical pulses are sent into the muscles and nerves, doctors then measure the pulses and nerve activity to see if it is working properly.